Femto-second profile moniitor using pulsed laser storage in an optical cavity

We have been developing a pulsed-laser storage technique in a super-cavity for a compact x-ray sources. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, using 357MHz mode-locked Nd:VAN laser pulses which stacked in a super-cavity scattered off a multi-bunch electron beam, we obtained a multi-pulse x-rays through the laser-Compton scattering. Detecting an x-ray pulse-by-pulse using high-speed detector makes it possible to measure the 3-dimensional beam size with bunch-by-bunch scanning the laserwire target position and pulse timing. This technique has a feasibility of measuring femto-second bunch length by stacking femto-second pulse in an optical cavity. Design study of femto-second laser-wire monitor and the experimental demonstration using pico-second pulse storage and multi-bunch electron beam will be presented at the conference.